Course ES
← back to chapter

Sticker maker

The same generation call, but the app wraps your subject in a fixed style recipe

Showcase — Sticker maker

The same generation call, but the app wraps your subject in a fixed style recipe — die-cut, bold outline, flat colors, white background — so every result is on-brand. It's prompt templating aimed at images: the user brings the subject, the app brings the look.

Run

bash bootstrap-secrets.sh              # reads ../../../../.env, writes secrets/
docker compose up --build              # default: PROVIDER=openai

Open http://localhost:3000. Gemini: PROVIDER=gemini docker compose up --build.

What's where

  • backend/ai_openai.py / backend/ai_gemini.py — the style template around the user's subject, returning a data URI.
  • frontend/app/page.tsx — subject box; renders the sticker.

Stop

docker compose down

Run locally

Download the project as a ZIP and run it with Docker. Brings up a FastAPI backend + Next.js frontend on localhost:3000.

Download sticker-maker.zip

unzip sticker-maker.zip
cd sticker-maker
bash bootstrap-secrets.sh   # one-time: pulls API keys into ./secrets
docker compose up --build   # default provider: openai
# or:  PROVIDER=gemini docker compose up --build

Type some input, pick a provider, and run the same code shown in Source against the live API. Sign-in required.


  

The same modules the Run button hits. The whole project (frontend, Dockerfile, compose) is in the ZIP under README.

backend/ai_openai.py

"""Showcase 2 (OpenAI): sticker maker.

The same generate call, but the app wraps your subject in a fixed style recipe —
die-cut sticker, bold outline, flat colors, white background. Prompt templating
for images: the user supplies the subject, the app supplies the look, so every
result is on-brand.
"""
from openai import OpenAI

_client = OpenAI()

_MODEL = "gpt-image-1"

_STYLE = ("A die-cut sticker of {subject}. Bold clean outline, flat vibrant "
          "colors, simple shading, centered on a plain white background, glossy "
          "vinyl sticker style.")


def run(subject: str) -> str:
    s = subject.strip()
    if not s:
        return "Describe the sticker subject (e.g. 'a happy avocado')."
    response = _client.images.generate(model=_MODEL, prompt=_STYLE.format(subject=s), size="1024x1024")
    return f"data:image/png;base64,{response.data[0].b64_json}"

backend/ai_gemini.py

"""Showcase 2 (Gemini): sticker maker via the image model.

Same style recipe wrapped around the user's subject; Gemini's image model via
generate_content.
"""
import base64
import os

from google import genai
from google.genai import types

_client = genai.Client(api_key=os.environ["GEMINI_API_KEY"])

_MODEL = "gemini-2.5-flash-image"

_STYLE = ("A die-cut sticker of {subject}. Bold clean outline, flat vibrant "
          "colors, simple shading, centered on a plain white background, glossy "
          "vinyl sticker style.")


def _generate(prompt: str) -> str:
    response = _client.models.generate_content(
        model=_MODEL, contents=prompt,
        config=types.GenerateContentConfig(response_modalities=["TEXT", "IMAGE"]),
    )
    for part in response.candidates[0].content.parts:
        if getattr(part, "inline_data", None) and part.inline_data.data:
            b64 = base64.b64encode(part.inline_data.data).decode()
            return f"data:image/png;base64,{b64}"
    return "No image was generated — try a different subject."


def run(subject: str) -> str:
    s = subject.strip()
    if not s:
        return "Describe the sticker subject (e.g. 'a happy avocado')."
    return _generate(_STYLE.format(subject=s))

Project files

  • .gitignore
  • README.es.md
  • README.md
  • backend/Dockerfile
  • backend/ai_gemini.py
  • backend/ai_openai.py
  • backend/main.py
  • backend/requirements.txt
  • bootstrap-secrets.sh
  • docker-compose.yml
  • frontend/Dockerfile
  • frontend/app/layout.tsx
  • frontend/app/page.tsx
  • frontend/next.config.ts
  • frontend/package.json
  • frontend/tsconfig.json